Conversion of hydrocarbon oil



July 14, 1936. I c ANGELL v 2,647,761

CONVERSION OF HYDROCARBON OIL Filed May 31, 1952 FURNACE RECEIVER FURNACE INVENTOR CHARLES H. ANGELL Patented July 14, 1936 UNITED STATES PATENT OFFICE,

CONVERSION OF HYDROCARBON OIL Charles H. Angel], Chicago, 'IlL, assignor to Universal Oil Products Company, Chicago, 11]., a corporation of Delaware Application May 31, 1932, Serial No. 614,369

4 Claims.

This invention relates to the conversion of hydrocarbon oil of either low boiling or high boiling characteristics, or of wide boiling range containing both high and low boiling components, and is particularly directed to the production therefrom of maximum yields of light distillate, such as motor fuel of high anti-knock value, accompanied by the production of either residual liquid of controlled quality or petroleum coke, as the residual product of the system.

More specifically the invention provides for the separation of relatively light and relatively heavy intermediate conversion products of the system, boiling above the end-boiling point of the desired light distillate product, subjecting the relatively heavy intermediate conversion products to milder conversion conditions than those to which the lighter intermediate conversion products are subjected and, after removing residual liquid conversion products from the former, commingling the resulting vapors with a the more highly heated oil, subjecting the commingled vaporous products to continued conversion at their attained temperature and subjecting the residual liquid conversion products, quickly separated from the vapors, to further distillation at reduced pressure. The hot commingled vapors, after their continued conversion for a predetermined time, may be subjected to fractionation for the separation of said light and heavy intermediate conversion products (from the final light distillate product and gas, or may first be commingled, all or'in part, with the residual liquid in the reduced pressure vaporizing chamber to assist vaporization of the residual oil as a means of controlling its quality and, when desired, such distillation of the residual oil may be carried to the point of reduction to coke.

As a special feature of the invention, the raw oil charging stock for the process is preferably supplied to the fractionator of the system and separated together with the intermediate conversion products of the process into light and heavy fractions, the heaviest componentsof the raw oil being subjected to conversion together with the heavy intermediate conversion products while lower boiling components of the charging stock are subjected to conversion together with the light intermediate conversion products. However, when the charging stock is of a relatively heavy nature entirely suitable for conversion under the conditions to which the heavy intermediate conversion products of the process are diate conversion products are returned. On the other hand, when the charging stock is of a relatively light nature, entirely suitable for conversion under the conditions to which the light intermediate conversion products are subjected, 5 the total raw oil may be supplied to the same heating coil to which said light intermediate conversion products are returned.

By separating the relatively light and relatively heavy oils and subjecting each to treatment in a separate heating coil, more selective conversion is possible than when a single heating coil is employed for the conversion of both light and heavy oils, permitting the maximum production of the desired products from both the light and the heavy fractions. By quick separation of residual liquid conversion products and by their quick removal from the reaction zone too rapid conversion of this heavy material and the formation of excessive quantities of coke and; gas may be prevented. By commingling the vaporous conversion products from both heating coils, subsequent to the removal of residual liquid conversion products, vapors resulting from conversion of the light fractions may be cooled sufli-. ciently to prevent their excessive conversion and the formation. of high yields of gas while vapors resulting from conversion of the heavier fractions may be heated to a higher conversion temperature or to a temperature suflicient to permit their continued conversion, the commingled. vapors being subjected to continued conversion time in the reaction zone at a temperature sufficient to insure a product of high anti-knock value.

As already mentioned, the optional feature of introducing all or a portion of the hot commingled vapors from the reaction chamber into direct contact with the residual liquid undergoing flash distillation permits control of the quality of the residual product of the system. This product may range from a substantial yield of good quality residual liquid, when little or no heated vapors are introduced toassist its vaporization, to lower yields of petroleum coke of low volatile content when all of the heated vapors are passed through the residual material. Control of the pressure in the flash distilling or coking zone as l well as the conversion conditions utilized in the heating coils and reaction chamber are other factors entering into the control of the quality of the residual product of the system. 1 V

The features ofthe invention and the advantages obtainable from their use mayv be more Qllifilillf understood by reference to the accompanying diagrammatic drawing and the following description thereof. The drawing illustrates one specific form of apparatus embodying the features of the present invention, and the following description of the drawing includes a description of the operation of the process as it may be practiced in the apparatus illustrated.

Referring now to the drawing, raw oil charging stock for the system is supplied through line I and valve 2 to pump 3, from which it may be fed in any of several directions, as already indicated. When the raw oil is a relatively heavy oil, such as heavy fuel or residual oil, it may be fed from pump 3 through lines 4, 5, I, valve 8 and line I5 to heating coil 11. When the charging stock is a relatively light oil such as kerosene distillate, naphtha, straight-run gasoline or the like, it may be fed from line 3 through line 4, line 5, valve 6 and line 24 to heating coil 26. When a charging stock of. relatively wide boiling range is utilized such as,-f or example, crude oil or topped crude,

heavy gas 'oil, light fuel oil, etcetera, it is preferably fed frompump 3 through line 4, line 9 and valve 10 into fractionator I I, wherein it commingles with the vaporous conversion products undergoing fractionation in'this zone and wherein its components are separated, together with the intermediate conversion products of the system boiling above the end-boiling point of the desired final light distillate product, into relatively light and relatively heavy fractions.

The heavy components of the intermediate conversion products of the process collect as heavy reflux condensate in the lower portion of the fractionatorand are withdrawn therefrom through line l2 and valve E3 to pump I 4 from which they are supplied'through line [5 and valve 16 to heating coil I! for further conversion, to-

gether with any heavy components of the raw oil, when the. raw oil is supplied to fractionator ||,-0"1- together with the total raw oil, when it is supplied, as already described, through line I and valve 8. The lower boiling components of the reflux'condensate may be withdrawn as one "ora plurality of side streams from the upper portio'n'of the fractionator, for example, through line2l and valve 22 to pump 23 from which this material is fed through line 24 and valve'25 to 'heatingcoil 26 for further conversion, together with any components of the charging stock of corresponding boiling range, when the raw oil is supplied to fractionator II, or together with the total-charging stock when supplied, as described,

through line 5 and valve 6.

Heating coil I1 is located within a furnace I8 of 'any suitable form wherein the oil supplied to this zone is heated'to the desired conversion temperature, preferably at substantial superatmospheric'pressure. The heated oil from heating coil ll is'discharged through line l9 and valve 20 into the lower portion of reaction chamber 30.

Reaction chamber 30 is also preferably maintained at substantial superatmospheric pressure "an'dresidual liquid products are quickly separated from the vaporous conversion products in the lower portion of the chamber. The residualliq- *uid is quickly'removed from the reaction chamber through line 3| and valve 32 and is introduced into a reduced pressure chamber 33 whereinits further'vaporization and, when desired, reduction 'a higher conversion temperature than that utilized in heating coil' [1, by means of heatsupbut at a point above the point of introduction of heated oil from heating coil l1, thus preventing intimate contact between the highly heated vaporous products from heating coil 26 and the residual liquid separated from the products from heating coil I1 but establishing intimate contact and commingling of the vaporous products from both heating coils.

Commingling of the vaporous conversion products from the two heating coils, in the manner described, permits the use of higher temperatures in heating coil 26 than would be otherwise advantageous, due to the fact that the products from this heating coil are somewhat cooled in the reaction chamber, at the same time milder conversion conditions may be employed in heating coil I'I than would otherwise be advantageous because the vaporous conversion products from this zone may be heated to a higher temperature in the reaction chamber, thus the heavy coke-forming components of the oil supplied to heating coil 1 1 maybe subjected to mild conversion conditions and may be removed from the reaction zone without excessive conversion while the lighter components from both heating coils may be subjected to continued conversion time in the reaction chamber at a temperature suitable for the pro- "duction of high yields of motor fuel of high antiknock value.

The commingled vaporous conversion products are withdrawn'from the upper portion of chamber 30 through line 34 and may pass through valve35 in this line, directly to fractionator I l or,

all or any desired portion of the hot vaporous products may be diverted from line 34 through line 36 and'valve 31 into chamber 33, to commingle with and heat the residual material in this zone, assisting vaporization of the residual oil andfwhendesired, effecting its reduction to coke.

Non-vaporous residual liquid, when such is produced, may be withdrawn from chamber 33 through line 38 and valve 39 to cooling and storage'or toany desired further treatment. When the residual product of the system is reduced to coke it may-be allowed to accumulate in chamber 33 to be removed therefrom after the operation of the chamber is discontinued. It is, of course,

' within the'scope of the invention to employ a plurality ofcoking chambers, similar to chamber 33 but not illustrated in the drawing, which may be operated either alternately or simultaneously to provide additional space for the'deposition of coke and prolong the operating cycle of the process. Vapors-from chamber 33 pass through line 40,

. valve 4| and line 34 to fractionation in fractionator II.

The vaporous products from the cracking and flash distilling or coking operations are separated in fractionator H into three streams. The components'of the vaporous products boiling above the end-boiling point of the desired light chstillate product of the system arecondensed within the fractionator and arbitrarily separated, as already-indicated, into relatively light and relatively heavy components. The heavy reflux condensate is supplied, as alreadyshown, to heating coil 'I'l while the light reflux condensate is supplied as'already shown, to heating coil 26.

1; .Tlrezthird: or roverheadt stream" from: the. fracionator-comprisesfuncondensable gas and .vaporus'prQducts-sfromLthe" system boilingwithint the :1 desiredxgas'olineboilinglrange which the charging ithdrawn inWaporousistate through line 42 and alve 43; is. subjected to condensation and'cooling 45.;an-d .valve 46' to collection in receiver 48. Un-

1-15: ondensable gas may be released from the receiv- =;,-:'e1:,throughtline 49 :and: valve 50. Distillate is wwithdrawnzfrom the-receiver through line 5| and :treatment.

.- 0 The heating coiltowhich the relatively heavy reflux condensate is, supplied, together with the 1:.-. heavy.components"or the total charging stock,

as thercase may be, may utilize'a conversion temperature ranging from 800 to 950. F. and, in most Icasesypreferably ,withinthe range of 350 to 900 7 F. with substantial:superatmospheric pressure,- wWhicIr'may range from 100 to 500 pounds, or-

ture ;than that"employed for the treatment of 1 .the heavy-reflux, ranging; for example, from 900 to 1'l00 Fpand preferablyflnmost cases, from 950 to ;1000 F:, more or less, preferably with superatmospheric pressure which may range from 100 to 800 pounds,'more or less, per square winch. Operating pressures of 1100 to-:500 pounds, 1 I or thereabouts, per. square inch may be employed.

in thewreaction'.chamber. The vaporizing or g qra-coking chamber is preferably operated at a sub- 1 stantially-reduced-pressure relative to thatem- -uiployed inthezreaction chamber, ranging, for exr ample', from lOO-pounds per square inchdown to substantial atmospheric pressure and the pressure in theysucceeding*fractionating; condensing a sand collecting "portions of the system may be sub- -istantiallwequalized or reduced,'relative to that employed in :theevaporizing chamber.

As aspecifio exampleof one particular typeof ,1 operation which "may be? practiced, in accordance L with the' features of the invention in an'apparatus r wrsuch as iillustrated and described; the raw oil chargi-ng'stock is a 42.8 A. P. I. gravity Oklahoma crude containing 30 to 35% of material ofgood anti-knock va-luesboiling up to 350 F. and containing approximately of material boiling up to 550 F. The crude oil is supplied to the 60 fractionator of the system wherein its components, other than gasoline of good anti-knock value, are separated together with the intermediate conversion products of the process into two cuts, the lighter of which has an initial boiling point of approximately 350 F. while the heavier fraction has an initial boiling point of approximately 550 F. The heavy cut of condensate and unvaporized portions of the crude oil from the 7 fractionator are subjected to .a temperature of approximately 900 F. at a superatmospheric pressure of about 400 pounds per square inch and is introduced into the lower portion of the reaction chamber wherein the residual oil is quickly sepa- 75 rated therefrom and withdrawn to a reduced oilingtrange oftherdesired' light .distillate product. mWhen'J-rawz:oilmcharging stock" is 'fed. into ,z

fractionator" Hi1. this "overhead .stream I from the l 1' z'fracticnator willwinclude;any'components of the:

pressure coking :szone. :The light outf of refiux condensate is subjected in a separate heating coil to a temperature of approximately 975 at a superatmospheric pressure of about500 pounds per square inch and this highly heated oil iscom-f" 5 mingled in. the reaction chamber with the-vaporous products. resulting from conversion? of the heavy reflux, afterthe residual oil has beensepaisstocko.mayucontain. :Thisoverheadrstream is .rated therefrom. I 1 .The .commingled'vapors are subjected to conic tinued' 'conversiontime .as they 'pass. upward through the reaction chamber and are then passed through the body of residualmaterial. in t the reduced pressure coking zone.

porous products of the system pass from the col-" The totalvaing. zone to the same fractionator to which the "crude oil chargingstock issupplied; Thisopera,'.1valve":52 tostorage or: to any. desired further ation may. yield, per barrel of .chargingJstock,

about 77% of motor fuel havingan octane number: of approximately 72, about 40 pounds of pe troleum coke and about 650.cubic feet ofuncondensable gas.

. As *a specific example of another type of=opera tion within the scope of the present invention, the

raw. oil charging stock is a Mid-Continentresidual 'oil of about? 20 A. P. Iggravity, all ofwhich is subjected together with heavy reflux condensate from the fractionator of the system to'atemperature of about 890 F. at'a 'superatmospheric pres;

. sure of approximately 350 pounds per square incli? The heated rawoil and heavy reflux condensate is introduced into the lower portion of the reac- 1 vtion chamber from which the residual liquid is quickly withdrawn to flash distillation- Apressure of about350 pounds per squareinch is main tained in the reaction chamber and is reduced in the flash distilling chamber to about 40 pounds per square inch. Light reflux condensate from the-fractionator of the system having a boiling orange of approximately 400 to 600 F. is subjected' o in aseparate heating coil to a temperature of approximately 970 F. at a superatmospheric pressure of about 400 pounds per squareinchas is then commingled with the-vaporous products in the reaction chamber. The commingledvapors' are subjected to continued conversion time as they pass upward through the reaction chamberw- A portion of the commingled'vapors is introduced into the body of residual oil in the flash distilling chamber and the remainder passeddirectly to th fractionator. This operation may yield, per-barrel of charging stock, about of motor fuel having an'anti kn'ock valueequivalentto atroctane number of approximately '75, about 30% of.

residual oil, marketable as fuel, and about-700 cubic feet of uncondensable gas.

i when flash distillation of the residual oil is accomplished without introduction of any-portion of the heated vaporous products from the reaction chamber a slightly higher yield of residual oil of 60 somewhat lighter character may be produced and the yield of motor fuel is reduced accordingly.

By employing a temperature of about 900 F. in the first heating coil with other operating con- 65 ditions substantially the same as given in the second example except that substantially atmospheric pressure is employed in the coking zone to which the residual oil from the reaction chamber is introduced and all of the commingled hot vaporous products from the upper portion of the reaction chamber are introduced into direct contact with the residualmaterial in the coking zone, the process may yield about 70% of motor fuel having an octane number of approximately 77,

about pounds of coke and about 900 cubic feet of gas.

I claim as my invention:

1. A cracking process which comprises maintaining hydrocarbon oil under cracking conditions of temperature and pressure in an enlarged vertical reaction zone, separately removing vapors and unvaporized oil from the upper and lower portions respectively of said zone, flash distilling the unvaporized oil by pressure reduction, combining the flashed vapors and the first-mentioned vapors, fractionating the commingled vapors and separating therefrom relatively heavy and light reflux condensates, containing insufliciently cracked fractions and flashed fractions, passing the heavier condensate through a heating zone and heating the same therein to cracking temperature under pressure, passing the lighter condensate through a second heating zone and heating the same therein to higher cracking temperature than the heavier condensate, discharging the thus heated condensates into the lower portion of said reaction zone and here separating the same into vapors and unvaporized oil, promptly withdrawing the latter from the reaction zone to said flash distilling step, passing the separated vapors upwardly through the reaction zone whereby they are subjected to continued conversion, and finally condensing the fractionated vapors.

2. A cracking process which comprises maintaining hydrocarbon oil under cracking conditions of temperature and pressure in an enlarged vertical reaction zone, separately removing vapors and unvaporized oil from the upper and lower portions respectively of said zone, flash distilling the unvaporized oil by pressure reduction, combining the flashed vapors and the first-mentioned vapors, fractionating the commingled vapors in contact with charging oil for the process and separating from the contacting vapors and charging oil relatively heavy and light liquid portions containing insufliciently cracked fractions, flashed fractions and charging oil fractions, passing the heavier liquid portion through a heating zone and heating the same therein to cracking temperature under pressure, heating the lighter liquid portion in a second heating zoneto higher cracking temperature than said heavier portion, discharging the thus heated oils into the lower portion of said reaction zone and here separating the same into vapors and unvaporized oil, promptly Withdrawing the latter from the reaction zone to said flash distilling step, passing the separated vapors upwardly through the reaction zone whereby they are subjected to continued conversion and finally condensing the fractionated Vapors.

3. A cracking process which comprises maintaining hydrocarbon oil under cracking conditions of temperature and pressure in an enlarged vertical reaction zone, separately removing vapors and unvaporized oil from the upper and lower portions respectively of said zone, flash distilling the unvaporized oil by pressure reduction, introducing said vapors into contact with the unvaporized oil being flash distilled and thereby combining the flashed vapors and the first-mentioned vapors, fractionating' the commingled vapors and separating therefrom relatively heavy and light re- 1 flux condensates containing insufficiently cracked fractions and flashed fractions, passing the heavier condensate through a heating zone and heating the same therein to cracking temperature under pressure, passing the lighter condensate 1 through a second heating zone and heating the same therein to higher cracking temperature than the heavier condensate, discharging the thus heated condensates into the lower portion of said reaction zone and here separating the same into vapors and unvaporized oil, promptly Withdrawing the latter from the reaction zone to said flash distilling step, passing the separated vapors upwardly through the reaction zone whereby they are subjected to continued conversion, and finally 2 condensing the fractionated vapors.

4. A cracking process which comprises maintaining hydrocarbon oil under cracking conditions of temperature and pressure in an enlarged vertical reaction zone, separately removing vapors 3 and unvaporized oil from the upper and lower portions respectively of said zone, flash distilling the unvaporized oil by pressure reduction, introducing said vapors into contact with the unvaporized oil being flash distilled and thereby 3 combining the flashed vapors and the first-mentioned vapors, fractionating the commingled vapors in contact with charging oil for the process and separating from the contacting vapors and charging oil relatively heavy and light liquid portions containing insufficiently cracked fractions, flashed fractions and charging oil fractions, passing the heavier liquid portion through a heating zone and heating the same therein to cracking temperature, under pressure, heating the I lighter liquid portion in a second heating zone to higher cracking temperature than said heavier portion, discharging the thus heated oils into the lower portion of said reaction zone and here separating the same into vapors and unvaporized oil, promptly withdrawing the latter from the reaction zone to said flash distilling step, passing the separated vapors upwardly through the reaction zone whereby they are subjected to continued conversion, and finally condensing the fractionated vapors.

CHARLES H. ANGELL. 

